As disk drives for storing data have improved in data density, data capacity, and response times, it is apparent that a higher reliability level of magnetic recording disks must be provided with respect to both data signal recording and operability. One factor affecting operability and reliability of a disk drive is the quality of the bond between the substrate of a disk and the magnetic recording media coated thereon to form the magnetic recording layer.
Delamination of the magnetic recording media layer from the glass disk substrate is one cause of disk failures. Both the disk and magnetic recording media are subject to very large and severe centrifugal forces due to the very high revolutionary speeds of a disk during disk drive operation.
Previously, polishing and texturing of a glass disk substrate would result in relatively deep gouges and grooves which could harbor abrasive polishing particles, glass particles and chips, and/or contaminants from chemical strengthening baths; these are examples of debris which commonly can result from a polishing operation and ion exchange processes. Debris is an obstacle to reliable and complete adherence of the magnetic recording media coating to the glass substrate. Wherever a weak or nonexistent bond between the coating and the disk substrate occurs, the bond strength and coating strength are inadequate to prevent delamination of the magnetic recording media coating or layer and results in disk failures.
Additionally, the roughness of a glass disk surface can be a deleterious factor in coating the glass disk substrate and can prevent production of a very smooth surface of the magnetic recording media final surface. The roughness of the final surface also affects or at least influences the flight characteristics of the read/write head and, consequently, the quality of the read and record signals.